BACKGROUND & AIMS: The standard treatment for patients with infected pancreatic necrosis (IPN) is surgical necrosectomy. We compared the outcomes of surgical treatment versus primary conservative treatment (patients kept in intensive care unit and treated with antibiotics, organ support, intensive nutritional support, and, if required, percutaneous drainage) among patients with IPN.METHODS: We performed retrospective comparative (with prospectively acquired database) and prospective observational studies; data were collected from all consecutive patients with acute pancreatitis (n = 804), and those with IPN formed the study group. Patients with IPN were divided into 2 groups on the basis of diagnosis of IPN during 1997-2002 (group 1, n = 30) or 2003-2006 (group 2, n = 50). Eighteen patients in group 1 were treated by surgical necrosectomy, and 40 patients in group 2 were given primary conservative treatment; surgery was performed on patients if conservative treatment failed (n = 10). The primary outcome measure was mortality.RESULTS: The mortality was comparable in group 1 versus group 2 (43% vs 28%; P = .22). During a period of 10 years, the patients who received primary conservative treatment had significantly higher survival rates than those who received surgery (76.9% vs 46.4%; P = .005). In the prospective study during 2007-2008, the mortality from infected necrosis was 29.6% after primary conservative treatment, confirming the results of the comparative study.CONCLUSIONS: In treating patients with IPN, a primary conservative strategy resulted in mortality that was comparable with that after surgery, and 76% of the patients were able to avoid surgery; 54.5% of IPN patients were successfully managed with the primary conservative strategy.